Also I invited @leonerd to join the repo because I am begging for his help.

Preview release
https://metacpan.org/release/TOBYINK/Class-CorX-0.000_001

Short answer: no idea.
Longer answer: You're not supposed to be fiddling with the inner core bits of the class stuff like that. It probably won't work - as you've discovered. Really you'll want to be using the meta:: API stuff to do it properly, but that doesn't exist yet. If you want to help please help make that first and then all of this will be simpler.

Longer answer: You're not supposed to be fiddling with the inner core bits of the class stuff like that.

Well, yeah. But as it's documented in perlclassguts, I figured it's at least a partly usable API. I guess I'll see if anybody on StackOverflow has any idea.

Really you'll want to be using the meta:: API stuff to do it properly, but that doesn't exist yet.

Indeed, but I wanted a hackish solution that can act as a stop-gap until that exists.

If you want to help please help make that first and then all of this will be simpler.

Happy to help out with that in any way I can.

Happy to help out with that in any way I can.

There's a PPC document for the meta:: stuff here: Perl/PPCs#25

That needs some finishing off, tidying up, agreeing, and then large amounts of actual implementing. Most of the initial implementation will be really boring writing simple XS code to do basically what things like Package::Stash already do. Honestly at this point the task is about 80% "people-pleasing" and 20% "writing code".